1. Field of the Invention
The present invention concerns locking devices for reciprocating members, and more particularly, reciprocating member locking devices of the type engaging a groove circumferentially disposed about the reciprocating member.
2. Description of the Prior Art
A reciprocating member is any form of uniformly shaped, generally elongated member, repetitively displaced along its longitudinal axis by an actuating mechanism. Reciprocating members are commonly configured as a shaft. Devices incorporating reciprocating members are well known in the prior art and enjoy a substantial number of diverse applications. Typical of devices incorporating a reciprocating member are hydraulic or pneumatic actuators. These devices usually include a piston slidingly disposed within an actuating mechanism and connected to a shaft extending beyond the actuating mechanism through a suitably configured aperture. The shaft is repetitively displaced along its longitudinal axis by the introduction of either a fluid or gas working fluid into the actuating mechanism to effect displacement of the internally disposed piston. Reciprocating members are also similarly incorporated into a wide range of devices relying on electromechanical or mechanical displacement actuators.
It is frequently desirably to lock a reciprocating member in a preselected position, commonly at its fullest extension from or retraction into an actuating mechanism. Suitable locking devices are usually disposed entirely within the actuating mechanism or located externally adjacent thereto. Reciprocating member locking devices are also well known in the prior art. A typical locking device, disclosed in U.S. Pat. No. 2,678,538, involves a pair of semi-circular jaws frictionally gripping a reciprocating shaft. Locking devices of this general nature suffer from a defect in that axially oriented displacement forces exceeding the frictional restraining force of the jaws can dislodge the reciprocating shaft. Another typical locking device, disclosed in U.S. Pat. No. 3,398,651, involves a rod engaging a circumferential groove in a reciprocating member. While locking devices of this nature do provide more secure locking by avoiding the need to rely on frictional restraining forces, these devices often fail to provide a uniform distribution of displacement restraining force about the circumference of the reciprocating member. Thus, there still exists a need to provide a locking device securely restraining a reciprocating member by engaging a circumferential groove disposed thereon while further uniformly distributing restraining forces about the circumference of the reciprocating member.